While it may be fashionable in some circles to doubt the provenance of climate change, there is no doubt that our oceans are warming and becoming more acidic. And even though a pH drop of 0.1 units may not sound that drastic, the reality is that ocean acidity has increased by 26% since the beginning of the Industrial Revolution, and the change is only going to accelerate. Although many fish appear to be able to tolerate the acidity shift physically, it is not clear how molluscs that cling to life on the wave-battered shoreline will cope. Elliot Scanes from the University of Sydney, Australia, explains that oysters that are routinely exposed to the air as the tide recedes may be better prepared for more acidic conditions than shore-mates that live beneath the tide: when the tide goes out, bivalves exposed above the waves close their shells, which restricts water flow over the gills and leads to a natural accumulation of CO2 – and acidification – of their tissues. Could this regular exposure to more acidic conditions leave high-and-dry Sydney rock oysters better prepared for future climate change than their perpetually immersed cousins, or could the additional stress tip them over the edge? (…)
Knight K., 2017. High and dry oysters at most risk from climate change. Journal of Experimental Biology 220:734. Article.